Timing calibration apparatus and method in a semiconductor integrated circuit tester

Abstract

There are provided a timing calibration apparatus and a timing calibration method capable of carrying out the calibration of timing on an IC tester with high accuracy. There is provided a probe to be sequentially contacted with pins of an IC socket on which an IC under test is to be mounted, and a calibration pulse supplied to the IC socket from the IC tester is taken in the probe. The calibration pulse is compared with the reference timing, thereby to calibrate the timing on a driver included signal path. In the probe a calibration pulse is generated, which is sequentially supplied to the pins of the IC socket, thereby to calibrate the timing on a comparator included signal path in each of channels. There are provided in the probe an optical modulator for converting an electric signal into an optical signal and an optically driven type driver. An optical cable couples between a calibration controller provided in the IC tester and the probe.

What is claimed is:  
     
       1. A timing calibration apparatus in an IC tester, said IC tester comprising: 
       an IC socket on which an IC under test is to be mounted;  
       signal paths including drivers respectively, each applying a calibration pulse to said IC socket;  
       a probe to be sequentially contacted with terminals of said IC socket to take therein a calibration pulse applied to the IC socket;  
       signal paths including comparating means respectively, each being connected with corresponding one of the terminals of the IC socket and being supplied through the IC socket with a calibration pulse having the reference phase generated from said probe; and  
       timing calibration means for conforming a signal propagation time on each of said driver included signal paths to the reference value as well as conforming the applied timing of each of strobe pulses given to the comparating means to the predetermined reference phase of the calibration pulse,  
       said timing calibration apparatus comprising:  
       an optically driven type driver provided in said probe; and  
       an optical drive signal supply means provided in said IC tester for supplying an optical drive signal to said optically driven type driver to generate the calibration pulse having the reference phase from the optically driven type driver.  
     
     
       2. A timing calibration apparatus in an IC tester, said IC tester comprising: 
       an IC socket on which an IC under test is to be mounted;  
       signal paths including drivers respectively, each applying a calibration pulse to said IC socket;  
       a probe to be sequentially contacted with terminals of said IC socket to take therein a calibration pulse applied to the IC socket;  
       signal paths including comparating means respectively, each being connected with corresponding one of the terminals of the IC socket and being supplied through the IC socket with a calibration pulse having the reference phase generated from said probe; and  
       timing calibration means for conforming a signal propagation time on each of said driver included signal paths to the reference value as well as conforming the applied timing of each of strobe pulses given to the comparating means to the predetermined reference phase of the calibration pulse,  
       said timing calibration apparatus comprising:  
       an optical modulator provided in said probe for modulating quantity of light in correspondence to the amplitude value of a calibration pulse taken in said probe from said IC socket; and  
       a photoelectric converter provided in said IC tester for converting the quantity of light of the modulated optical signal transmitted from said optical modulator into an electric signal and supplying the electric signal to comparating means to which a strobe pulse is to be applied.  
     
     
       3. A timing calibration apparatus in an IC tester, said IC tester comprising: 
       an IC socket on which an IC under test is to be mounted;  
       signal paths including drivers respectively, each applying a calibration pulse to said IC socket;  
       a probe to be sequentially contacted with terminals of said IC socket to take therein a calibration pulse applied to the IC socket;  
       signal paths including comparating means respectively, each being connected with corresponding one of the terminals of the IC socket and being supplied through the IC socket with a calibration pulse having the reference phase generated from said probe; and  
       timing calibration means for conforming a signal propagation time on each of said driver included signal paths to the reference value as well as conforming the applied timing of each of strobe pulses given to the comparating means to the predetermined reference phase of the calibration pulse,  
       said timing calibration apparatus comprising:  
       an optically driven type driver provided in said probe;  
       an optical drive signal supply means provided in said IC tester for supplying an optical drive signal to said optically driven type driver to generate the calibration pulse having the reference phase from the optically driven type driver;  
       an optical modulator provided in said probe for modulating quantity of light in correspondence to the amplitude value of a calibration pulse taken in said probe from said IC socket; and  
       a photoelectric converter provided in said IC tester for converting the quantity of light of the modulated optical signal transmitted from said optical modulator into an electric signal and supplying the electric signal to comparating means to which a strobe pulse is to be applied.  
     
     
       4. The timing calibration apparatus as set forth in  claim 1  or  3 , wherein said optically driven type driver comprises: a plurality of photoconductive elements, each coming to electrically conductive state by applying light thereon; and a plurality of voltage supplies selected by said plurality of the photoconductive elements respectively, and for generating voltages corresponding to a logical signal. 
     
     
       5. The timing calibration apparatus as set forth in  claim 2  or  3 , wherein said optical modulator has such a structure that an electric field formed by the voltage of the calibration pulse is applied to either one of branched two optical waveguides, the direction of said electric field being orthogonal to the travelling direction of light, and said optical modulator is one of the type which modulates light by utilizing a delay of light caused by application of the electric field to light and varying the quantity of light of an interference light obtained by that the branched two lights have been unified. 
     
     
       6. The timing calibration apparatus as set forth in  claim 1  or  3 , wherein said optically driven type driver is coupled to said optical drive signal supply means by an optical cable. 
     
     
       7. The timing calibration apparatus as set forth in  claim 2  or  3 , wherein said optical modulator is coupled to said photoelectric converter by an optical cable. 
     
     
       8. A timing calibration method in an IC tester, said IC tester comprising: 
       an IC socket on which an IC under test is to be mounted;  
       signal paths including drivers respectively, each applying a calibration pulse to said IC socket;  
       a probe to be sequentially contacted with terminals of said IC socket to take therein a calibration pulse applied to the IC socket;  
       signal paths including comparating means respectively, each being connected with corresponding one of the terminals of the IC socket and being supplied through the IC socket with a calibration pulse having the reference phase generated from said probe; and  
       timing calibration means for conforming a signal propagation time on each of said driver included signal paths to the reference value as well as conforming the applied timing of each of strobe pulses given to the comparating means to the predetermined reference phase of the calibration pulse,  
       said timing calibration method comprising the steps of:  
       converting, in said IC tester, an electric signal outputted from a waveform formatter into an optical signal;  
       supplying said optical signal to a photoconductive element of an optically driven type driver provided in said probe; and  
       generating the calibration pulse having the reference phase from said optically driven type driver.  
     
     
       9. A timing calibration method in an IC tester, said IC tester comprising: 
       an IC socket on which an IC under test is to be mounted;  
       signal paths including drivers respectively, each applying a calibration pulse to said IC socket;  
       a probe to be sequentially contacted with terminals of said IC socket to take therein a calibration pulse applied to the IC socket;  
       signal paths including comparating means respectively, each being connected with corresponding one of the terminals of the IC socket and being supplied through the IC socket with a calibration pulse having the reference phase generated from said probe; and  
       timing calibration means for conforming a signal propagation time on each of said driver included signal paths to the reference value as well as conforming the applied timing of each of strobe pulses given to the comparating means to the predetermined reference phase of the calibration pulse,  
       said timing calibration method comprising the steps of:  
       modulating, in said probe, quantity of light of a propagating light in correspondence to the amplitude value of a calibration pulse taken in said probe from said IC socket; and  
       converting the quantity of light of the modulated optical signal transmitted to said IC tester from said probe into an electric signal; and  
       supplying the electric signal to comparating means and conforming the timing of the calibration pulse to the timing of a strobe pulse which is to be applied to said comparating means.